Sensitivity to formalin treatment and affinity measurement of recombinant antibodies. (a) Recombinant antibodies SI1-Unc5b and SI2-Unc5b were tested for formalin fixation sensitivity by ELISA following antigen treatment with a 4% formalin solution. (b-e) The dissociation rates of the recombinant (red line) antibodies were compared to the original hybridoma antibodies (blue line) using surface plasmon resonance. Antibodies are: (b) SI3-Flrt3, (c) SI4-Jamc.2, (d) SI2-Unc5b and (e) SI5-Lrrn1. In order to facilitate comparison, binding at saturation was normalized to 100% and rebinding was minimized by immobilizing low levels of target protein and washing at 37°C using high flow rates (100 μL/min).